Linear alpha-olefin, which is an important material used in a comonomer, a detergent, a lubricant, a plasticizer, or the like, is commercially widely used. Particularly, 1-hexene and 1-octene are mainly used as a comonomer for adjusting density of polyethylene when preparing linear low-density polyethylene (LLDPE).
In a process of preparing linear low-density polyethylene (LLDPE) according to the related art, a comonomer such as alpha-olefin, for example, 1-hexene and 1-octene, was copolymerized together with ethylene in order to form a branch in a polymer backbone to adjust density.
Therefore, in order to prepare LLDPE in which a content of the comonomer is high, there was a problem in that a cost of the comonomer was a large part of a manufacturing cost. In order to solve this problem, various methods have been attempted.
In addition, since an application field or a market size of alpha-olefin is different according to the kind thereof, commercially, a technology of selectively producing specific olefin is significantly important. Recently, research into a chromium catalyst technology for preparing 1-hexene or 1-octent with high selectivity through selective ethylene oligomerization has been mainly conducted.
As a commercial preparation method of 1-hexene or 1-octene according to the related art, there are the Shell higher olefin process (SHOP) process from Shell Chemical, the Ziegler process from Chevron Philips, and the like, and (C4˜C10) alpha-olefin having wide molecular weight distribution may be prepared.
In addition, various researches into a technology of selectively preparing 1-hexene or 1-octene by an ethylene trimerization or tetramerization method using an organic metal catalyst have been conducted, but there was a disadvantage in that in the case of supporting the organic metal catalyst on a support such as silica, activity was significantly decreased (J. Am. Chem. Soc. 2003, 125, 5272, Ind. Eng. Chem. Res. 2008, 47, 5369).